Photo of Aimie Zdrantan who was murdered by her boyfriend in Hillsboro in August 2014.

HILLSBORO, OR (KPTV) -

A man who murdered his girlfriend while on work release from jail will spend the rest of his life behind bars.

Eric Petersen, 25, pleaded guilty to the charge of aggravated murder Wednesday. He was sentenced to life in prison without the possibility of parole.

Aimie Zdrantan, 24, was found dead in her home at the Minter Bridge Square apartments in Hillsboro in August 2014.

Prosecutor Bracken McKey on Wednesday in court described it as a "horrible, vicious, premeditated murder" with Petersen beating Zdrantan and stabbing her.

Zdrantan and Petersen's 2-year-old daughter was in the apartment at the time of the killing.

McKey said Petersen was serving a 60-day jail sentence at the time of the murder, and had only served 10 days when he was released on a job-related day pass.

"Aimie had no reason to think this defendant would be at her door the morning of Aug. 28," McKey said.

Zdrantan had a restraining order against Petersen. McKey said she had made it clear she no longer wanted anything to do with Petersen, and Petersen told other inmates he was going to kill her in the days before he carried out the crime.

McKey said the system needs to change to focus on community safety, saying currently it's a "system where offenders are called clients and inmates are called residents as if this is a hotel and the staff is acting as nothing more than a concierge."

He suggested either GPS or in-person monitoring for offenders allowed to leave jail for any reason before their sentence is served.

"Essentially they get to do anything that we get to do in our everyday lives," he said.

Zdrantan's father agreed that changes need to be made.

"When they make a call to release somebody with a prior history, a violent history at that, they should never have that opening and unfortunately that was overlooked," Steve Zdrantan said outside the courtroom.

A Washington County Community Corrections spokesman said changes were made following a grand jury's annual review that took place after Petersen's arrest.

Now, any offender being held on a domestic violence-related crime or for a sexual offense will be placed on GPS monitoring when released on day passes.

Inmates also can no longer get a day pass during their first 14 days at the restitution center.

Steve Zdrantan said he was satisfied that Petersen received a "true life sentence."

"Unfortunately he did not admit to also the rape and robbery and whatever else he did that day, but it's sufficient enough to close the case," he said.

Petersen was initially also facing charges including burglary and sex abuse, but those charges were dismissed with his guilty plea to aggravated murder.

Aimie Zdrantan's mother also addressed Petersen in court Wednesday, but Petersen did not make a statement.

Nearly two weeks after 16-year-old Amy Yu vanished with 45-year-old Kevin Esterly, the pair was found Saturday in Mexico and the man was arrested, authorities say. (Allentown Police Department)

Nearly two weeks after a 16-year-old Pennsylvania girl vanished with a 45-year-old man, the pair was found Saturday in Mexico and the man was arrested, authorities say. Amy Yu was "unharmed and in good health."

Nearly two weeks after a 16-year-old Pennsylvania girl vanished with a 45-year-old man, the pair was found Saturday in Mexico and the man was arrested, authorities say. Amy Yu was "unharmed and in good health."

The Eugene Police Department’s spokesperson, Melinda McLaughlin, says there has been eight robberies in Eugene in two weeks and several of those happened just a block or two from the University of Oregon.

The Eugene Police Department’s spokesperson, Melinda McLaughlin, says there has been eight robberies in Eugene in two weeks and several of those happened just a block or two from the University of Oregon.